Come to think of it ... all human activities however complex and obtuse, are derived from just two fundamental needs - to be able to eat, and to be able to procreate. Period.

Out of the simple need to eat derives the complex systems of production, transport, distribution and consumption of food (and further on, the systems that support and maintain these systems). You can think of a hundred everyday activities that all derive justification out of a need to eat!!

Out of the simple need to procreate, derives the complex system of creating a conducive and nourishing environment within which children can grow (and further on, the systems that support and maintain these systems).